Lance Armstrong is in a boat bobbing in Kailua Bay, a little shark’s-fin inlet on the west coast of the Big Island of Hawaii. The water is an intense, travel-brochure blue, with a gentle breeze and sunshine sparkling on the waves – the kind of place where you wouldn’t mind dropping anchor and wasting away the rest of your life.

Armstrong is about to swim two and a half miles in it.

"Time to put on the ol’ grape smuggler," Armstrong says. He wraps a towel around his waist and starts to strip. Off comes the Livestrong® cap, the Livestrong® T-shirt, the Livestrong® shorts, the Livestrong® sunglasses, the Livestrong® shoes. He grabs his Livestrong® Speedo and pulls it on, snugly encasing the most famous testicle in sports. He jumps in the water.

"Shit, it’s cold!" he says when he surfaces. Slowly, a mischievous smile spreads across his face. "But it’s warm right here."

Armstrong’s coach, a wiry ex-triathlete named Jimmy Riccitello, is beside him on a standup paddleboard. He points to a reddish-­orange speck on the horizon about the size of a laser-pointer dot. "See that orange buoy?" he says. "Past the boat?"

"I don’t even see the boat," Armstrong says.

"Just follow me," says Riccitello.

Armstrong starts swimming. Just so we’re clear: 2.4 miles is a hell of a long swim. Imagine doing a length in your local pool, 25 meters, one end to the other. Then imagine doing 153 more. He swims past coconut stands, souvenir shops, rocky beaches, sandy beaches, jet skiers, a kayaker, a hang-glider, and an unsuspecting family of snorkelers.

After about 25 minutes, he reaches the buoy. On the side, in thick black lettering, are two words: ironman turnaround.

Assuming everything goes according to plan, this October – 16 years after his cancer diagnosis and seven after his last Tour de France win – the 41-year-old Armstrong will compete here in Kona in the Ironman World Championship, probably the most grueling single-day endurance event in the world. The first one was run in 1978, a competition started by a former Navy Commander to see who was fitter, runners or swimmers. The original pitch: "Swim 2.4 miles! Bike 112 miles! Run 26.2 miles! Brag for the rest of your life!" Now as many as 70,000 compete in Ironman events each year. "It’s this badge of honor," says Armstrong. "Like doing a marathon or climbing Everest. ‘I did a fucking Ironman.’ They just want to finish."

Armstrong, of course, does not just want to finish. He wants to do what he’s always done, from Plano, Texas, to the Pyrenees: He wants to win. "I certainly don’t have the confidence or cojones to say I’m going to win," he says, his eyes steely. "But I’m very comfortable saying I want to win. And I want to start winning right away. If everything goes right, I’ll be there in any race. To win the Ironman is very difficult. You can’t screw up nutrition or hydration; no mechanical or technical problems. Basically you can’t make any mistakes. But man," he says, grinning. "It’d be cool."

During his peak years, between 1999 and 2005, when he won an unprecedented seven consecutive Tours de France, Armstrong’s riding weight was around 165 pounds. Lately all the swimming he’s been doing has added some upper-body bulk, so now he’s closer to 170. But in another way, he’s racing lighter than he has in years.

Until very recently, Armstrong was under federal investigation for possible crimes including fraud, money laundering, tax evasion, and drug distribution – all related to the long-standing, vehemently denied, circumstantially-­suspicious-but-never-actually-proven charges that he won those Tours with the aid of performance-­enhancing drugs. Had he been indicted, he likely would have faced jail time, not to mention untold millions in fines and legal bills. In darker moments, Armstrong told friends that he feared the worst. But in February, the case was suddenly and without explanation dropped. "I’ve essentially been given my life back for a second time," he says, alluding to the testicular cancer that almost killed him 16 years ago. "It’s all good."

For Armstrong, there are business advantages to doing the Ironman – including a reported million-dollar donation from the race to the Lance Armstrong Foundation. But there’s something else pushing him, too, a tiny voice echoing at the back of his head – the voice of the doubters, the skeptics, the Armstrong haters. He knows he’ll never win over all of them, but if he can win the Ironman, a tiny part of him thinks, then maybe, just maybe, he might win over some.

"There aren’t too many people on the fence about me," he says. "But if I am on the fence, maybe I look at [an Ironman win] and go, ‘I don’t know what to believe. But this fucking guy has been at the top for 25 years, they’ve thrown everything they could at him, and dammit, the guy is still there.’

"I want this bad," he says. "If I thought it was cool and good for business, I could just go through the motions and have a respectable finish. But I don’t want to be given the charity slot and get 20th. I want to win."

Back at the buoy, Armstrong takes a breather on the paddleboard. We’re way out there. The purr of the boat’s motor is the only sound. He takes a few deep breaths, looks back at the city in the distance. "All right," he says. "Let’s go home."

Tom Brokaw: Do you ever imagine going back and doing a triathlon?Armstrong: Yeah, for sure. I would actually be more inclined to do an Xterra, an off-road triathlon. That’s with a mountain-bike course and a trail run.Brokaw: Are you tempted by the Ironman?Armstrong: No. —Men’s Journal, July 2006